Here a little tutorial how to download free line sticker for other country using vpn.
1. Open line app and select more->setting->account. Make sure your line account link with facebook. And if you have register with phone number, after link with facebook, remove this app and reinstall again. Than select log in with facebook. Because this will not work with phone number register.
2. Download this 2 app from app store :
Hope this can help. Thanks